• Korean Chemical Engineering Research
• /
• v.58 no.2
• /
• pp.235-247
• /
• 2020

Simulation study and validation on 50 L/hr pilot-scale Bunsen process was carried out in order to investigate thermodynamics parameters, suitable reactor type, separator configuration, and the optimal conditions of reactors and separation. Sulfur-Iodine is thermochemical process using iodine and sulfur compounds for producing hydrogen from decomposition of water as net reaction. Understanding in phase separation and reaction of Bunsen Process is crucial since Bunsen Process acts as an intermediate process among three reactions. Electrolyte Non-Random Two-Liquid model is implemented in simulation as thermodynamic model. The simulation results are validated with the thermodynamic parameters and the 50 L/hr pilot-scale experimental data. The SO₂ conversions of PFR and CSTR were compared as varying the temperature and reactor volume in order to investigate suitable type of reactor. Impurities in H₂SO₄ phase and HI_X phase were investigated for 3-phase separator (vapor-liquid-liquid) and two 2-phase separators (vapor-liquid & liquid-liquid) in order to select separation configuration with better performance. The process optimization on reactor and phase separator is carried out to find the operating conditions and feed conditions that can reach the maximum SO₂ conversion and the minimum H₂SO₄ impurities in HI_X phase. For reactor optimization, the maximum 98% SO₂ conversion was obtained with fixed iodine and water inlet flow rate when the diameter and length of PFR reactor are 0.20 m and 7.6m. Inlet water and iodine flow rate is reduced by 17% and 22% to reach the maximum 10% SO₂ conversion with fixed temperature and PFR size (diameter: 3/8", length:3 m). When temperature (121℃) and PFR size (diameter: 0.2, length:7.6 m) are applied to the feed composition optimization, inlet water and iodine flow rate is reduced by 17% and 22% to reach the maximum 10% SO₂ conversion.

• Journal of Korean Society of Forest Science
• /
• v.55 no.1
• /
• pp.59-67
• /
• 1982

The objectives of this report is to evaluate the contribution of forest investments by the forest owners for the developments of private forests in the villages where the forest production, especially, chestnut production is active. The results obtained are as follows : 1) Newly purchased forest lands of 526 hectares, 71 percent, in 741 hectares by 96 farmers were replanted with chestnut trees for chestnut production. 2) As the chestnut production is considered to be the unique source of the early capital return in management of forests, selling and buying of forest lands in the area surveyed are enhanced to reforest the forest land with chestnut seedlings. 3) Most of new farmers being engaged in plantation and production of chestnuts in the forests are employees of private industries and government agencies, and merchants in neighboring towns. 4) All materials and expenses for formation of chestnut orchards are generally supplied by forest land owners. 5) Active buying and selling of newly established chestnut bushes are surely served as the estate in the area, thus, the trading of the bushes of young chestnut seedling also enhances the forest as the estate. 6) The management of forest established with chestnut orchards is a special form for forest investment, it makes possible to encourage imputing of capital to the new form of forests, chestnut orchards, and it could be a good possible model for private forest development as compared with that of government funding.

• KDI Journal of Economic Policy
• /
• v.32 no.2
• /
• pp.144-170
• /
• 2010

This paper considers the effect of various types of procurement auction system on competition focusing on the rate of successful bidding. We analyze the number of bidders and the rate of successful bids using online procurement data of the Public Procurement Service. The average number of bidders is 301 and the average rate of successful bids is 87.42% while the weighted average rate is 75.13%. These numbers show that there is quite strong competition among bidders and the rate is lower as the expected price is higher. When we analyze the data of price procurement auction, the rate is also shown to be lower as the expected price is higher. Furthermore, the rate decreases as the number of bidders increases which naturally makes the competition stronger. Meanwhile, the analysis finds that the inclusion of the onsite bidding, the PQ(Pre-Qualification) result, or major-10 winning companies cannot explain the rate much in our data. In case of turnkey-alternative, the average rate of successful bidding for 484 cases record 90.20%. The average is 84.89% with 120 alternatives and 91.97% with 364 cases of turnkey. The reason why the rate of turnkey-alternative is lower than that of price procurement auction is the lack of competition as well as the systematic difference. By setting up a model, we are able to explain the difference in rate caused by the respective reason. When we suppose there are 3 bidders in case of price procurement auction for a project that exceeds 100 billion won, the rate is expected to be around 64%. This implies that difference of 26% is caused by the systemic difference and 3% by the lack of competition. Therefore, we conclude that the difference in rate between turnkey-alternative and price procurement auction is caused mainly by the systemic difference. In case of PPP(Public Private Partnership) projects, among 154 projects in total, only 40% has more than 2 bidders that compete. The average number of bidders is 1.88 which is less than 2, and the average rate of successful bids is 90%. In sum, under the price procurement auction, there is strong competition which is reflected by the rate of successful bids. However, there is room to decrease the rate by strengthening the competition under the turnkey-alternative. Also with PPP projects, we expect the rate can be steadily reduced with revived competition among bidders.

• Korean Journal of Construction Engineering and Management
• /
• v.17 no.4
• /
• pp.103-115
• /
• 2016

The 106 buildings of 200 meters' height or greater were completed around the world in 2015 (CTBUH, The Council on Tall Buildings and Urban Habitat). They beat every previous year on record, including the previous record high of 99 completions in 2014. This brings the total number of 200-meter-plus buildings in the world to 1,040, exceeding 1,000 for the first time in history and marking a 392% increase from the year 2000, when only 265 existed. South Korea recorded three completions during 2015 - improving slightly over 2014, in which it had one. This study focused on the fact that high-rise building development project risks have not reduced in Korea in spite of numerous studies and measures. And it attempted to examine whether existing studies and measures have been presented on the basis of the accurate analysis of existing studies and measures and classify and analyze the characteristics of each phase' s risk factors in the hope that its results would be one reference point as to the measure to prevent high-rise building development project risks in the future. A high-rise building development project is the high risk project as compared with the low-rise project. Because a high-rise development project takes long and is very sensitive to the changing environment. Therefore, in order to succeed the project it becomes necessary to effectively manage the risk involved in the process of the high-rise building development project. The result of this study can be used as the guideline to make the risk management system for the high-rise development project.

• The Korean Journal of Financial Management
• /
• v.21 no.2
• /
• pp.27-63
• /
• 2004

Since the 1980s, many multinational corporations have been issuing stocks on foreign stock exchanges, not only to enhance their investor base and liquidity, but also to diversify risks. The phenomenon has also been intensified by the rapid financial globalization and securitization trends. The main purpose of this study is to look into the long-run performance of MNCs' cross-listings of stocks on foreign stock exchanges. We use the event study and cross-sectional regression methods. We obtained some interesting empirical results about the long-run effect of cross-listings. First before the listing data the effect of cross-listing is to increase the underlying stock Vice in the local market. It may be caused by expectation of lower risk and cost of capital. However, after the listing data the stock price has been declining, even if it is not significant. Second, we examine the difference in the long-run cross-listing effect, which may be caused by the listing direction. When listing is made from a less developed market to a more developed market, the effect is better than that in the reverse direction. Furthermore, the effect is worse, when the listing company's home country is the U.S. Third, there is a negative relation between CARs and underlying stock liquidity in the local market, So it implies that a firm, whose underlying stocks are very liquid in the local market should carefully value cross-listing based upon the cost and benefit analysis. Last, but not the least we find that the long-un cross-listing effect is better, when a listing firm's ROE is higher.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.30 no.5
• /
• pp.909-928
• /
• 2020

From the early 1970s, the US government began to recognize that penetration testing could not assure the security quality of products. Results of penetration testing such as identified vulnerabilities and faults can be varied depending on the capabilities of the team. In other words none of penetration team can assure that "vulnerabilities are not found" is not equal to "product does not have any vulnerabilities". So the U.S. government realized that in order to improve the security quality of products, the development process itself should be managed systematically and strictly. Therefore, the US government began to publish various standards related to the development methodology and evaluation procurement system embedding "security-by-design" concept from the 1980s. Security-by-design means reducing product's complexity by considering security from the initial phase of development lifecycle such as the product requirements analysis and design phase to achieve trustworthiness of product ultimately. Since then, the security-by-design concept has been spread to the private sector since 2002 in the name of Secure SDLC by Microsoft and IBM, and is currently being used in various fields such as automotive and advanced weapon systems. However, the problem is that it is not easy to implement in the actual field because the standard or guidelines related to Secure SDLC contain only abstract and declarative contents. Therefore, in this paper, we present the new framework in order to specify the level of Secure SDLC desired by enterprises. Our proposed CIA (functional Correctness, safety Integrity, security Assurance)-level-based security-by-design framework combines the evidence-based security approach with the existing Secure SDLC. Using our methodology, first we can quantitatively show gap of Secure SDLC process level between competitor and the company. Second, it is very useful when you want to build Secure SDLC in the actual field because you can easily derive detailed activities and documents to build the desired level of Secure SDLC.

• Journal of Korea Technology Innovation Society
• /
• v.12 no.4
• /
• pp.687-714
• /
• 2009

In this paper, we study empirically the relations between financial constraints and dividend adjustment speed of innovative small and medium sized enterprises (SMEs) listed on Kosdaq Market of Korea Exchange. The main results of this study can be summarized as follows. Determinants suggested by the major theories of dividends, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory explain significantly the dividend payout policy of Kosdaq SMEs. Lintner's dividend adjustment model indicates that Kosdaq SMEs have long run target payout ratio, and that Kosdaq SMEs adjust partially the gap between actual and target payout ratio each year. In the core variables of Lintner (1956) dividend adjustment model, past DPS has more effect than current EPS. These results suggest that Kosdaq SMEs maintain stable dividend policy which maintain past DPS level without corporate special reasons. Dividend adjustment speed of innovative Kosdaq SMEs is more fast than that of uninnovative Kosdaq SMEs, and dividend adjustment speed of financial unconstrained innovative Kosdaq SMEs is faster than that of financial constrained innovative Kosdaq SMEs. Futhermore, dividend adjustment speed of innovative Kosdaq SMEs classified by Small and Medium Business Administration is faster than that of unclassified innovative Kosdaq SMEs. The former is linked with financial policies and services like credit guaranteed service, venture investment fund, insurance program, and so on. In conclusion, past DPS and current EPS suggested by the Lintner's dividend adjustment model explain mainly dividend adjustment speed, and financial constraints explain also partially. Therefore, if managers of innovative Kosdaq SMEs can properly understand of the effects of financial constraints on dividend smoothing, they can maintain constantly dividend policy. This is encouraging result for Korea government as it has implemented many policies to commit to innovative Kosdaq SMEs.

• Journal of Intelligence and Information Systems
• /
• v.21 no.1
• /
• pp.143-159
• /
• 2015

Predicting IT trends has been a long and important subject for information systems research. IT trend prediction makes it possible to acknowledge emerging eras of innovation and allocate budgets to prepare against rapidly changing technological trends. Towards the end of each year, various domestic and global organizations predict and announce IT trends for the following year. For example, Gartner Predicts 10 top IT trend during the next year, and these predictions affect IT and industry leaders and organization's basic assumptions about technology and the future of IT, but the accuracy of these reports are difficult to verify. Social media data can be useful tool to verify the accuracy. As social media services have gained in popularity, it is used in a variety of ways, from posting about personal daily life to keeping up to date with news and trends. In the recent years, rates of social media activity in Korea have reached unprecedented levels. Hundreds of millions of users now participate in online social networks and communicate with colleague and friends their opinions and thoughts. In particular, Twitter is currently the major micro blog service, it has an important function named 'tweets' which is to report their current thoughts and actions, comments on news and engage in discussions. For an analysis on IT trends, we chose Tweet data because not only it produces massive unstructured textual data in real time but also it serves as an influential channel for opinion leading on technology. Previous studies found that the tweet data provides useful information and detects the trend of society effectively, these studies also identifies that Twitter can track the issue faster than the other media, newspapers. Therefore, this study investigates how frequently the predicted IT trends for the following year announced by public organizations are mentioned on social network services like Twitter. IT trend predictions for 2013, announced near the end of 2012 from two domestic organizations, the National IT Industry Promotion Agency (NIPA) and the National Information Society Agency (NIA), were used as a basis for this research. The present study analyzes the Twitter data generated from Seoul (Korea) compared with the predictions of the two organizations to analyze the differences. Thus, Twitter data analysis requires various natural language processing techniques, including the removal of stop words, and noun extraction for processing various unrefined forms of unstructured data. To overcome these challenges, we used SAS IRS (Information Retrieval Studio) developed by SAS to capture the trend in real-time processing big stream datasets of Twitter. The system offers a framework for crawling, normalizing, analyzing, indexing and searching tweet data. As a result, we have crawled the entire Twitter sphere in Seoul area and obtained 21,589 tweets in 2013 to review how frequently the IT trend topics announced by the two organizations were mentioned by the people in Seoul. The results shows that most IT trend predicted by NIPA and NIA were all frequently mentioned in Twitter except some topics such as 'new types of security threat', 'green IT', 'next generation semiconductor' since these topics non generalized compound words so they can be mentioned in Twitter with other words. To answer whether the IT trend tweets from Korea is related to the following year's IT trends in real world, we compared Twitter's trending topics with those in Nara Market, Korea's online e-Procurement system which is a nationwide web-based procurement system, dealing with whole procurement process of all public organizations in Korea. The correlation analysis show that Tweet frequencies on IT trending topics predicted by NIPA and NIA are significantly correlated with frequencies on IT topics mentioned in project announcements by Nara market in 2012 and 2013. The main contribution of our research can be found in the following aspects: i) the IT topic predictions announced by NIPA and NIA can provide an effective guideline to IT professionals and researchers in Korea who are looking for verified IT topic trends in the following topic, ii) researchers can use Twitter to get some useful ideas to detect and predict dynamic trends of technological and social issues.

• Journal of the Korean Geographical Society
• /
• v.28 no.4
• /
• pp.379-391
• /
• 1993

Present-day world economy is characterized by : technology nationalism, economic regionalism, market protectionism, multinational corporations, efc. All nations are striving for intensifying national economic rivalry and seeking after their own interests above everything else. Many regions of the world are also forming trading blocs, which could negatively affect nonmember states. The ultimate way to meet these difficulties is to establish production facilities in the countries imposing trade regulations. However, as the existing models of direct forrign investment (DFI) do not account for the particular nature of Korean firm's DFI activities, a new point of departure is imperative. It is because of this that Korean firms have only limited firm-specific advantages, the basic precondition of extant DFI theories, compared with their developed counterparts.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.4
• /
• pp.163-174
• /
• 2017

This study analyzed how Korean firms' recapitalization affects their capital structure decision and firm value. Recapitalization was categorized into three groups according to the influence of the debt to equity ratio: debt ratio-increasing-recapitalization(capital reduction with refund, cash dividend), debt ratio-unchanging-recapitalization (capital reduction without refund, retirement of repurchased stocks), and debt ratio-decreasing-recapitalization(exercise the rights for convertible bonds, bond with stock warrants, exchangeable bonds and stock options). This article highlights how the relationship between the firms' recapitalization and the capital structure decision driven by the change in debt to equity ratio through the recapitalization should affect the firm value. The whole recapitalization sample used for this analysis comprised 22,814 enterprises listed on the Korea Exchange that were analyzed over the 16-year period from 2000 to 2015. To summarize the results of this Panel Data Analysis, firstly, when a firm executes debt ratio-increasing-recapitalization and debt ratio-decreasing-recapitalization at the period of t-1, the debt to equity ratio, which is increased or decreased, should affect the firm's debt capacity in the same period, then, at the period of t, the firm establishes a leverage policy to readjust the debt to equity ratio the other way around. These adjustments of debt-paying-ability from the leverage policy, including the capital structure decision, finally affect the firm value. Secondly, when a firm implements the debt ratio-unchanging-recapitalization in the period of t-1, the debt to equity ratio, which is neutral, should not affect the firm's capital structure decision. But, the firm value is positively affected by the influence of that recapitalization. Conclusively, we acknowledge a firm which carries out the recapitalization balances its capital structure to the optimal level of leverage and that the capital structure decision positively affects the corporate value.